[DlcSettingsUi] Fix 'Remove' button disabled when it should not be.

Fixed: 1096770
Change-Id: I60f55f43534f3388801c1a5aca29f936861d7398
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2253128Reviewed-by: Esmael Elmoslimany <aee@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Regan Hsu <hsuregan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#785815}

chrome/browser/resources/settings/chromeos/device_page/dlc_subpage.html

@@ -64,8 +64,8 @@
             </div>
           </div>
           <cr-button
-              data-dlc-id$="[[item.id]]"
-              id="remove-button-[[index]]"
+              disabled="[[item.disabled]]"
+              data-index$="[[index]]"
               on-click="onRemoveDlcClick_"
               tabindex$="[[tabIndex]]"
               aria-describedby$="name[[index]] size[[index]]

chrome/browser/resources/settings/chromeos/device_page/dlc_subpage.js

@@ -46,18 +46,9 @@ cr.define('settings', function() {
      * @private
      */
     onRemoveDlcClick_(e) {
-      const removeButton = this.shadowRoot.querySelector(`#${e.target.id}`);
-      removeButton.disabled = true;
-      this.browserProxy_.purgeDlc(e.target.getAttribute('data-dlc-id'))
-          .then(success => {
-            if (success) {
-              // No further action is necessary since the list will change via
-              // onDlcListChanged_().
-              return;
-            }
-            console.log(`Unable to purge DLC with ID ${e.target.id}`);
-            removeButton.disabled = false;
-          });
+      const item = this.$.list.items[e.target.dataset.index];
+      item.disabled = true;
+      this.browserProxy_.purgeDlc(item.id);
     },
 
     /**